Many blogs have already discussed this, but I'll go ahead and throw my hat in the ring.
My Private Jet - the chameleon of OPI. And not like a duochrome, either. There have been several iterations of this popular color.
I originally picked up one bottle that happened be a holographic version, and I fell for it. Fell hard. I ordered FOUR more bottles. Unfortunately, those four came from different stock.
You can see the difference here:
On the left, one of the four 'duds'. There is still some teal flash in this bottle. But compared to the bottle on the right...
I tend to make use of my dud bottles by doing the initial coat with them, and the second coat with my holo bottle. Even the dud bottles are lovable - the charcoal + holo just seems so wearable - much less harsh than just black. Sigh, this is the color that really got me hooked on polish.